JP2017163649A - Control device and control method for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an electric vehicle which is capable of protecting switching elements in inverters from overhearing and allowing the vehicle to continue traveling even if a cooling water temperature sensor is failed.SOLUTION: An EV-ECU 14 cools inverters 6a, 6b in a power drive unit 6 in which the former converts power from a battery 7 and drives a motor 4 and the latter converts power from a generator 2 and stores it in the battery by means of cooling water and performs control of an electric vehicle by switching between an EV travel mode and power generation travel mode in accordance with detection values from a sensor group mounted on the electric vehicle, which includes switching element temperature sensors for switching elements of the inverters and a cooling water temperature sensor 12 for the cooling water. It detects a failure of the cooling water temperature sensor by means of a detection value from the cooling water temperature sensor, and if a failure of the cooling water temperature sensor is detected during the EV travel mode, uses a detection value detected by the switching element temperature sensor of the switching element of the inverter for the generator as a detection value of cooling water temperature.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device and control method for an electric vehicle including an EV (electric vehicle) and an HEV (hybrid electric vehicle), and more particularly to a failure of a coolant temperature sensor.

  In recent years, hybrid vehicles and electric vehicles have attracted attention as vehicles that take into account energy savings and the environment. A hybrid vehicle uses a motor as a power source in addition to a conventional engine, and an electric vehicle uses a motor as a power source.

Both the hybrid vehicle and the electric vehicle travel by driving the motor by converting the DC power stored in the battery into AC power using an inverter circuit.
The above-described inverter circuit is composed of switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and FETs (Field effect transistors), and the DC power is converted into AC power by ON / OFF control of the switching elements.
At this time, when the switching element is turned on and a current flows, the temperature of the switching element rises. For this reason, a temperature sensor that measures the switching element temperature is provided to limit the current flowing through the switching element so that the switching element temperature does not exceed the limit, and protection is performed so that the switching element is not destroyed.

  As an example of the above, in Patent Document 1 below, an inverter is controlled by an inverter ECU (Electronic Control Unit) to drive a motor, and the inverter ECU detects an inverter temperature based on an input from an inverter temperature sensor. When the inverter temperature suddenly rises, the inverter ECU protects the switching element by adjusting the torque command value to the inverter, that is, suppressing the motor output torque and reducing the heat generation amount of the switching element. A method is disclosed.

JP-A-10-210790

However, the technique described in Patent Document 1 does not assume a case where the coolant temperature sensor fails. Therefore, if the cooling water temperature sensor fails and the actual cooling water temperature becomes unknown, there is no problem if the cooling system is normal, but the cooling system is in an abnormal state due to leakage of cooling water or a water pump failure. Then, the cooling water temperature rises abnormally, and it becomes difficult to absorb the heat generated by the switching element with the cooling water. As a result, when the motor output torque is set to be normal when the cooling system is normal, that is, when the cooling water temperature is normal, the switching element cannot be protected and damaged. There is a possibility.
In addition, when a failure of the cooling water temperature sensor is detected, a method of immediately stopping the motor drive and protecting the switching element is conceivable. However, if there is no abnormality in the cooling system, the vehicle cannot be run unnecessarily. There is a problem.

  The present invention has been made to solve the above-described problem. Even if the coolant temperature sensor fails, the switching element in the inverter can be reliably protected from overheating, and the vehicle can continue to run. It is an object of the present invention to provide an electric vehicle control apparatus and control method that can be used.

  The present invention includes an inverter for a motor and an inverter for a generator, converts a power from a battery to drive a motor, converts a power from a generator and stores it in the battery, and each inverter. An inverter cooling device for cooling with cooling water, a switching element temperature sensor for detecting the temperature of the switching element of each inverter, and a sensor group mounted on the electric vehicle including a cooling water temperature sensor for detecting the temperature of the cooling water; A control unit that controls the electric vehicle, and the control unit switches the EV driving mode and the power generation driving mode according to a detection value from the sensor group, and controls the electric vehicle. And the electric vehicle control unit detects a failure of the cooling water temperature sensor in accordance with a detection value from the cooling water temperature sensor. A cooling water temperature sensor failure detection unit, and a detection detected by the switching element temperature sensor of the switching element of the generator inverter when a failure of the cooling water temperature sensor is detected in the EV travel mode. A control unit for an electric vehicle including a cooling water temperature sensor failure detection value reading unit whose value is a detection value of the cooling water temperature.

  According to the present invention, it is possible to provide a control device and a control method for an electric vehicle that can reliably protect the switching element in the inverter from being overheated even if the coolant temperature sensor breaks down and can keep the vehicle running continuously. .

It is a schematic block diagram of the control apparatus of the electric vehicle which concerns on one embodiment of this invention. It is a schematic circuit block diagram of the electric circuit part of PDU of FIG. It is the elements on larger scale explaining the schematic structure of the water jacket in PDU of FIG. It is a figure which shows an example of the motor maximum output torque suppression map used with the control apparatus of the electric vehicle which concerns on one embodiment of this invention. It is an operation | movement flowchart of an example of control of the electric vehicle at the time of the water temperature sensor failure of the control apparatus of the electric vehicle which concerns on one embodiment of this invention. It is a timing chart explaining vehicle operation when a cooling water temperature sensor fails in EV mode of an electric vehicle control device according to an embodiment of the present invention. It is a timing chart explaining vehicle operation | movement when a cooling water temperature sensor fails in the electric power generation driving mode of the control apparatus of the electric vehicle which concerns on one embodiment of this invention. It is a figure which shows an example of schematic hardware structure at the time of comprising EV-ECU of FIG. 1 with a computer.

  In the control device and control method for an electric vehicle according to the present invention, even when the cooling water temperature sensor that detects the cooling water temperature of the inverter fails, the motor driving is continued while protecting the switching element inside the inverter.

According to the control device and control method for an electric vehicle according to the present invention,
A switching element temperature sensor for detecting the temperature of the switching element of the inverter;
A cooling water temperature sensor for detecting the temperature of the cooling water;
A cooling water temperature sensor failure detection unit for detecting a failure of the cooling water temperature sensor,
When a coolant temperature sensor failure is detected by the coolant temperature sensor failure detection unit during EV (Electric Vehicle) travel mode,
By recognizing and replacing the switching element temperature detection value detected by the switching element temperature sensor of the generator inverter as the cooling water temperature,
Even if the cooling water temperature sensor breaks down, the correct cooling water temperature can be recognized, so that the switching element of the motor inverter can be protected from overheating while continuing the vehicle operation.

According to the control device and control method for an electric vehicle according to the present invention,
A motor maximum output torque suppression unit that suppresses the maximum output torque of the motor according to the cooling water temperature is further provided,
When the cooling water temperature sensor failure is detected by the cooling water temperature sensor failure detection unit during the power generation travel mode,
Stop driving the generator,
The difference between the cooling water temperature detection value before the cooling water temperature sensor failure detection unit detects the cooling water temperature sensor failure and the switching element temperature detection value detected by the switching element temperature sensor of the generator inverter is greater than the predetermined value. If so,
The motor maximum output torque suppression unit suppresses the maximum output torque of the motor,
If the value is below the specified value,
Since the switching element temperature detection value detected by the switching element temperature sensor of the generator inverter is recognized as the cooling water temperature,
Even if the cooling water temperature sensor breaks down, until the correct cooling water temperature can be detected, the motor maximum output torque suppression map assumes that the cooling water temperature is the maximum water temperature, for example, 110 ° C. By suppressing the output torque, the switching element of the motor inverter can be protected and the correct coolant temperature can be recognized, so that the vehicle operation can be continued without suppressing the torque. It is possible to protect the switching element from overheating while minimizing the uncomfortable feeling including a drop in torque.

  Hereinafter, a control device and a control method for an electric vehicle according to the present invention will be described with reference to the drawings according to embodiments. In each drawing, the same or corresponding parts are denoted by the same reference numerals.

Embodiment 1 FIG.
FIG. 1 is a schematic configuration diagram of a control device for an electric vehicle according to an embodiment of the present invention. In FIG. 1, a PDU (power drive unit) 6 that converts a DC voltage of the battery 7 into an AC voltage is provided between the battery 7 and the motor 4, which are power sources, and between the battery 7 and the generator 2. The PDU 6 includes a motor inverter 6a and a generator inverter 6b that can convert the DC voltage of the battery 7 into an AC voltage and supply the converted voltage to the motor 4 and the generator 2, respectively.

In the EV travel mode, the engine 1 is stopped and the generator 2 is not generating power. Therefore, the DC power stored in the battery 7 is converted into three-phase AC power by the motor inverter 6a and supplied to the motor 4. As a result, the motor 4 is driven, the tire 5 is further driven, and the vehicle is driven.
Further, when the vehicle is decelerated, the motor 4 is rotated by the tire 5, and the motor 4 performs regenerative power generation, and the generated electric power is charged to the battery 7 via the motor inverter 6a.

In the power generation travel mode, since the engine 1 is driven and the generator 2 is generating power, the generated power is charged into the battery 7 via the generator inverter 6b.
Then, the motor 4 is driven by converting the power generated by the generator 2 or the DC power stored in the battery 7 into AC power by the motor inverter 6 a and driving the motor 4, and further driving the tire 5. , Drive the vehicle.
When the vehicle is decelerated, the motor 4 is rotated by the tire 5, the motor 4 performs regenerative power generation, and the electric power generated by the regenerative power generation is charged to the battery 7 via the motor inverter 6a.
Further, the generator inverter 6 b converts the DC power stored in the battery 7 into AC power, drives the generator 2, and starts the engine 1.
Further, the vehicle can be driven by transmitting the driving force of the engine 1 to the tire 5 through the motor 4 by coupling the clutch 3.

In the following description, the series hybrid vehicle shown in FIG. 1 will be described as an example, but a parallel hybrid vehicle may be used.
The series type uses an engine only for power generation and uses a motor only for driving and regenerating an axle. The parallel system is a system in which a plurality of mounted power sources, that is, an engine and a motor are used for driving wheels. In FIG. 1, the configuration is a series type when the clutch 3 is disengaged and a parallel type when the clutch 3 is connected.
Further, as described above, the generator 2 and the motor 4 may be a motor / generator MG that combines driving and power generation.
Moreover, you may have a DC / DC converter (illustration omitted) etc. which perform voltage conversion between the battery 7 and inverter 6a, 6b.

  FIG. 2 is a schematic circuit configuration diagram of an electric circuit unit of the PDU 6. The PDU 6 includes a motor 4, a generator 2, a battery 7, a motor inverter 6 a that drives and controls the motor 4 by converting DC power stored in the battery 7 into AC power, and AC power generated by the generator 2. It is composed of an inverter 6b for a generator that converts into DC power and stores it in the battery 7.

The motor inverter 6a includes a U-phase switching circuit 105a, a V-phase switching circuit 106a, and a W-phase switching circuit 107a.
The U-phase switching circuit 105a includes an upper arm side switching circuit 105Ha on the upper arm 109a side and a lower arm side switching circuit 105La on the lower arm 110a side.
The V-phase switching circuit 106a includes an upper arm side switching circuit 106Ha on the upper arm 109a side and a lower arm side switching circuit 106La on the lower arm 110a side.
The W-phase switching circuit 107a includes an upper arm side switching circuit 107Ha on the upper arm 109a side and a lower arm side switching circuit 107La on the lower arm 110a side.

The switching circuits 105Ha-107Ha and 105La-107La are composed of switching elements such as IGBTs and FETs and free-wheeling diodes, and are controlled by the EV-ECU 14 described later.
In the example of FIG. 2, the switching element temperature sensors 105HaU, 106HaV, and 107HaW for measuring the switching element temperatures of the switching circuits 105Ha to 107Ha are provided on the upper arm 109a side. On the lower arm 110a side, switching element temperature sensors 105LaU, 106LaV, 107LaW for measuring the switching element temperatures of the switching circuits 105La-107La are provided. The EV-ECU 14 acquires the switching element temperature of each switching circuit, limits the current, that is, the output torque so as not to exceed the limit temperature, and protects the switching element from being destroyed.

The generator inverter 6b includes a U-phase switching circuit 105b, a V-phase switching circuit 106b, and a W-phase switching circuit 107b.
The U-phase switching circuit 105b includes an upper arm side switching circuit 105Hb on the upper arm 109b side and a lower arm side switching circuit 105Lb on the lower arm 110b side.
The V-phase switching circuit 106b includes an upper arm side switching circuit 106Hb on the upper arm 109b side and a lower arm side switching circuit 106Lb on the lower arm 110b side.
The W-phase switching circuit 107b includes an upper arm side switching circuit 107Hb on the upper arm 109b side and a lower arm side switching circuit 107Lb on the lower arm 110b side.

The switching circuits 105Hb-107Hb and 105Lb-107Lb are composed of switching elements such as IGBTs and FETs and free-wheeling diodes, and are controlled by the EV-ECU 14 described later.
In the example of FIG. 2, switching element temperature sensors 105HbU, 106HbV, and 107HbW that measure switching element temperatures of the switching circuits 105Hb to 107Hb are provided on the upper arm 109b side. On the lower arm 110b side, switching element temperature sensors 105LbU, 106LbV, and 107LbW for measuring switching element temperatures of the switching circuits 105Lb to 107Lb are provided. The EV-ECU 14 acquires the switching element temperature of each switching circuit, limits the current, that is, the output torque so as not to exceed the limit temperature, and protects the switching element from being destroyed.

Returning to FIG. 1, the vehicle dissipates heat generated by the operations of the switching circuits 105Ha-107Ha and 105La-107La of the motor inverter 6a and the switching circuits 105Hb-107Hb and 105Lb-107Lb of the generator inverter 6b to the outside. In order to do so, an inverter cooling device 8 is provided.
The inverter cooling device 8 includes a cooling water pipe 9 through which cooling water for cooling the PDU 6 having a switching circuit circulates, an electric water pump 10 that circulates the cooling water through the cooling water pipe 9, and heat exchange of the cooling water with outside air. A radiator 11 for cooling and a cooling water temperature sensor 12 for detecting the temperature of the cooling water are provided.

Further, both ends of the cooling water pipe 9 are connected to the PDU 6, and the cooling water sent by applying pressure from the electric water pump 10 flows in from the inlet portion 13 a and is discharged from the outlet portion 13 b to the radiator 11. The Also. Between the inlet portion 13a and the outlet portion 13b in the PDU 6b including the motor inverter 6a and the generator inverter 6b, a water jacket 13c through which cooling water flows is disposed as shown by an arrow CWC in FIG. ing.
The switching circuits of the upper arm 109a and lower arm 110a of the motor inverter 6a and the upper arm 109b and lower arm 110b of the generator inverter 6b are arranged on the water jacket 13c in order to ensure sufficient heat dissipation. It is installed. Thereby, heat generated by a switching element (not shown) in the switching circuit is absorbed by the cooling water through the water jacket 13c. The cooling water that has received the heat of the switching element is released to the outside in the radiator 11. Thereby, each switching circuit can be protected from overheating.

The vehicle further includes an electronic control unit (EV-ECU) 14 that is a control unit that comprehensively controls the vehicle.
A vehicle speed sensor 15 for detecting the vehicle speed,
An accelerator opening sensor 16 for detecting an accelerator operation amount;
A motor rotation speed sensor 17 for detecting the rotation speed of the motor 4;
A generator rotation speed sensor 18 for detecting the rotation speed of the generator 2;
An engine speed sensor 19 for detecting the speed of the engine 1, and
A cooling water temperature sensor 12 for detecting the temperature of the cooling water;
Switching element temperature sensor group (105HaU, 106HaV, 107HaW, 105LaU, 106LaV, 107LaW and 105HbU, 106HbV, 107HbW, 105LbU, 106LbV, 107LbW) for detecting the temperature of the switching element provided in PDU6,
Other sensors required for various controls not shown,
Detection signals indicating detection values from are respectively input.

  The EV-ECU 14 is based on the detection values from the respective sensors input as shown in FIG. 1, and the motor inverter 6a, the generator inverter 6b, the engine 1, the motor 4, the generator 2, the clutch 3, the electric pump 10 is controlled.

In addition, the EV-ECU 14 serving as a control unit switches the EV travel mode and the power generation travel mode in accordance with the detection values from the sensor group (105HaU-107LbW, 12, 15-19) and controls the vehicle. 14x and a storage unit M.
The electric vehicle control unit 14x
A coolant temperature sensor failure detection unit 14a for detecting a failure of the coolant temperature sensor 12,
A travel mode determination unit 14b that sets the travel mode according to the detection value from the sensor group (105HaU-107LbW, 12, 15-19);
A motor maximum output torque suppression unit 14c that suppresses the maximum output torque of the motor according to the coolant temperature detected by the coolant temperature sensor 12,
A cooling water temperature sensor failure detection value replacement unit 14d that replaces the detection value when the cooling water temperature sensor fails;
including.

  Here, when the coolant temperature sensor 12 is normally detecting the coolant temperature Tw, the current flowing through the switching element is adjusted in order to control the maximum output torque according to the coolant temperature. . Thereby, the motor 4 can be driven so that the temperature of the switching element does not exceed the limit temperature.

Like the motor maximum output torque suppression map shown in FIG. 4, the maximum output torque is suppressed using a map in which the horizontal axis is the cooling water temperature and the vertical axis is the maximum output torque suppression rate. For example,
Until the cooling water temperature reaches 70 ° C., the maximum output torque suppression rate is 1.0 (no suppression),
When the cooling water temperature is 90 ° C., the suppression rate is 0.6,
When the cooling water temperature is 110 ° C., the suppression rate is set to 0.2.
By suppressing the maximum output torque, the motor 4 can be controlled while protecting the switching element from overheating.
Further, as the cooling water temperature increases, the amount of heat that can be radiated from the switching element to the cooling water decreases, so the suppression rate decreases.
Since the motor maximum output torque suppression map for protecting the switching element from overheating in this way depends on the cooling water temperature, it is important to detect the accurate cooling water temperature.

However, when the cooling water temperature sensor 12 fails, the difference between the actual cooling water temperature and the detected value of the cooling water temperature sensor becomes large. Therefore, if the output torque is suppressed according to the motor maximum output torque suppression map shown in FIG. In some cases, the switching element cannot be protected from overheating.
Further, if the motor 4 and the generator 2 are simply stopped when the cooling water temperature sensor 12 fails, running becomes impossible.

  Therefore, in this embodiment, when the coolant temperature sensor fails, the EV-ECU 14 controls the electric vehicle described below according to the traveling state, that is, the EV traveling mode and the power generation traveling mode.

  FIG. 8 shows an example of a schematic hardware configuration of the EV-ECU 14 configured by, for example, a computer. Signals are input / output via the interface 141. The memory 143 stores in advance information data, tables, maps, etc., including various function programs indicated by function blocks in the EV-ECU 14 of FIG. 1 and the motor maximum output torque suppression map of FIG. 4 required for processing. Stored. The storage unit M in the EV-ECU 14 in FIG. 1 corresponds to the memory 143. The CPU 142 performs arithmetic processing on signals input via the interface 141 according to various programs, information data, tables, and maps stored in the memory 143, and outputs processing results via the interface 141.

  FIG. 5 shows an operation flowchart of an example of control of the electric vehicle when the water temperature sensor of the electric vehicle control device according to the embodiment of the present invention fails. This operation flowchart is repeatedly executed at a set cycle.

  In the EV-ECU 14, the electric vehicle control unit 14x controls the vehicle by switching between the EV travel mode and the power generation travel mode in accordance with the detection value from the sensor group (105HaU-107LbW, 12, 15-19). Switching between the EV travel mode and the power generation travel mode is performed by the travel mode determination unit 14b.

  In step S101, the cooling water temperature sensor failure detection unit 14a determines that the cooling water temperature sensor 12 has failed. Here, when the output voltage of the cooling water temperature sensor 12 exceeds a predetermined setting range, it is determined that the cooling water temperature sensor 12 has failed. Here, the setting range can be set in advance in consideration of the output voltage when the coolant temperature sensor 12 is disconnected or short-circuited. If it is determined in step S101 that the cooling water temperature sensor 12 is malfunctioning, the process proceeds to step S102, and if not, the process proceeds to step S103.

In step S102, the cooling water temperature sensor failure detection unit 14a sets the cooling water temperature sensor failure flag to “1”, and the process proceeds to step S104. In step S103, the coolant temperature sensor failure flag is reset to “0”.
In step S104, the cooling water temperature sensor failure detection unit 14a detects that the cooling water temperature sensor failure flag has changed from “0” to “1”, and has detected that the cooling water temperature sensor failure flag has changed from “0” to “1”. If so, the process proceeds to step S105, and if not, the process proceeds to step S106.

  In step S105, the cooling water temperature sensor failure detection unit 14a acquires a water temperature detection value Tw0 before detecting a failure of the cooling water temperature sensor 12. Specifically, the detection value of the cooling water temperature sensor 12 is saved in the storage unit M as time series data periodically (for example, at intervals of 100 ms). The coolant temperature sensor failure detection unit 14a changes the water temperature sensor failure flag from “0” to “1”, reads the value before detecting the failure of the coolant temperature sensor 12 from the storage unit M, and reads this value as the coolant The water temperature detection value Tw0 before the temperature sensor failure is detected.

  In step S106, the traveling mode determination unit 14b determines whether the traveling mode currently set based on the vehicle speed detected by the vehicle speed sensor 15 and the accelerator opening detected by the accelerator opening sensor 16 is the EV traveling mode. Then, it is determined whether the power generation traveling mode is set. If it is determined that the travel mode is the EV travel mode, the process proceeds to step S108. If it is determined that the current mode is the power generation travel mode, the process proceeds to step S107, and the electric vehicle control unit 14x stops driving the generator and continues this operation. As a result, electricity is not supplied to the generator inverter 6b, so that the switching circuits 105Hb-107Hb and 105Lb-107Lb do not generate heat.

  In step S108, the motor maximum output torque suppression unit 14c acquires the average value Tswg_ave of the switching element temperatures detected by the switching element temperature sensors 105HbU, 106HbV, 107HbW, 105LbU, 106LbV, and 107LbW of the generator inverter 6b. Proceed to S109.

In step S109, the motor maximum output torque suppression unit 14c determines the coolant temperature detection value Tw0 before detecting the coolant temperature sensor failure acquired in step S105 and the switching element temperature of the generator inverter 6b acquired in step S108. It is determined whether or not the absolute value of the difference from the average value Tswg_ave is within a predetermined set difference Tdiff, that is, | Tw0−Tswg_ave | ≦ Tdiff. If it is within the set difference Tdiff, actual cooling It is determined that the water temperature and the average value Tswg_ave of the switching element temperature of the generator inverter 6b substantially match, and the process proceeds to step S110. In step S110, the coolant temperature sensor failure detection value reading unit 14d recognizes the coolant temperature Tw as the average value Tswg_ave of the switching element temperature of the generator inverter 6b, and sets the coolant temperature Tw to the average value Tswg_ave. To end this routine.
Thereby, the electric vehicle control unit 14x controls the motor 4 by using the average value Tswg_ave of the switching element temperature as the cooling water temperature Tw, not the value acquired by the cooling water temperature sensor 12.

  Further, when the difference between the detected water temperature value Tw0 before detecting the cooling water temperature sensor failure acquired in step S105 and the average value Tswg_ave of the switching element temperature of the generator inverter 6b acquired in step S108 exceeds the set difference Tdiff. Determines that the actual cooling water temperature is different from the average value Tswg_ave of the switching element temperature of the generator inverter 6b, and proceeds to step S111.

In step S111, since the actual cooling water temperature is unknown, the motor maximum output torque suppression unit 14c suppresses the maximum output torque of the motor on the assumption that the cooling water temperature is the maximum temperature (eg, 110 ° C.). To do. Specifically, as shown in FIG. 4, when the cooling water temperature is 110 ° C., the maximum output torque suppression rate is 0.2.
Even when the actual cooling water temperature is unknown, assuming that the cooling water temperature is very high and the cooling of the switching element temperature is the least efficient, the motor maximum output torque is suppressed, preventing overheating of the switching element. While driving the motor, the vehicle can continue to travel.
Further, the motor maximum output torque suppression rate described above can be obtained by actual machine verification, and exceeds the heat resistance limit temperature (for example, 150 ° C.) of the switching element at each cooling water temperature (60 ° C., 70 ° C., 90, 110 ° C.). 4 is derived, and based on this result, the motor maximum output torque suppression map of FIG. 4 can be set and stored in the storage unit M for use.

6 and 7 are time charts showing the operation of this embodiment.
FIG. 6 shows the operation when the cooling water temperature sensor 12 fails in the EV traveling mode, the average value Tswg_ave of the switching element temperature of the generator inverter 6b is recognized as the cooling water temperature, and the motor drive is continued. It is a thing.
In 201, the solid line indicates the cooling water temperature Tw, and the broken line indicates the average value Tswg_ave of the switching element temperature of the generator inverter 6b. In this time chart, it is assumed that the actual cooling water temperature (not shown) is constant at 60 ° C. C represents a period during which the coolant temperature Tw is read as the average value Tswg_ave of the switching element temperature of the generator inverter 6b.
202 is a water temperature sensor failure flag according to steps S102 to S104 of FIG. 5, and is set to “1” when a failure of the cooling water temperature sensor, that is, the water temperature sensor is detected.
Reference numeral 203 denotes a driving state of the generator 2, and power generation is always stopped in the EV traveling mode.
Reference numeral 204 denotes the maximum output torque suppression rate of the motor 4, and the suppression rate is set according to the coolant temperature from the motor maximum output torque suppression map of FIG.

Next, the operation of FIG. 6 will be described. From the time t0 to the time t1, the motor inverter 6a converts the DC power stored in the battery 7 into three-phase AC power and supplies it to the motor 4, thereby driving the motor 4. In the EV travel mode, the generator 2 is stopped and the switching element of the generator inverter 6b does not generate heat, so the switching element temperature of the generator inverter 6b matches the coolant temperature.
When a failure of the coolant temperature sensor 12 is detected at time t1, the coolant temperature sensor failure flag is set to “1”, and the power generation stop of the generator 2 is continued. And the average value (60 degreeC) of the switching element temperature of the inverter 6b for generators is recognized as a cooling water temperature, and a motor drive is continued.
Further, the motor maximum output torque suppression rate is 1.0, that is, no suppression according to the torque suppression rate in the case of the coolant temperature of 60 ° C. shown in the motor maximum output torque suppression map of FIG. Thus, even if the cooling water temperature sensor 12 fails, the correct cooling water temperature can be detected, so that the switching element of the inverter can be protected from overheating while continuing the vehicle operation.

FIG. 7 shows that when the coolant temperature sensor 12 fails in the power generation travel mode, the driving of the generator 2 is stopped, the motor maximum output torque is suppressed, and the temperature of the switching element of the generator inverter 6b is decreased. This shows the operation when the motor driving is continued by recognizing the average value Tswg_ave of the switching element temperature of the generator inverter 6b as the cooling water temperature Tw. After replacing the cooling water temperature Tw, the suppression rate returns to 1.0.
In 301, the solid line indicates the cooling water temperature Tw, and the broken line indicates the average value Tswg_ave of the switching element temperature of the generator inverter 6b. In this time chart, it is assumed that the actual cooling water temperature (not shown) is constant at 60 ° C. C represents a period during which the coolant temperature Tw is read as the average value Tswg_ave of the switching element temperature of the generator inverter 6b. R represents a period during which the motor maximum output torque is suppressed.
302 is a water temperature sensor failure flag according to steps S102 to S104 of FIG. 5, and is set to “1” when a failure of the cooling water temperature sensor, that is, the water temperature sensor is detected.
Reference numeral 303 denotes a driving state of the generator 2. The generator 2 generates power in the power generation travel mode, and supplies the generated power to the motor 4 and the battery 7.
304 is the maximum output torque suppression rate of the motor 4, and the suppression rate is set according to the coolant temperature Tw from the motor maximum output torque suppression map of FIG.

Next, the operation of FIG. 7 will be described. From the time t0 to the time t1, the power generation travel mode in which the motor inverter 6a converts the power generated by the generator 2 by the driving force of the engine 1 or the DC power stored in the battery 7 into AC power to drive the motor 4. State. During this period, the generator 2 is generating power, and the switching element of the generator inverter 6b generates heat, so the switching element temperature of the generator inverter 6b is different from the cooling water temperature Tw.
When a failure of the coolant temperature sensor 12 is detected at time t1, the coolant temperature sensor failure flag is set to “1”, and the power generation of the generator 2 is stopped. Here, the maximum motor output torque suppression rate is set to 0.2 in accordance with the maximum cooling water temperature in the motor maximum output torque suppression map of FIG. 4, that is, the motor maximum output torque suppression map of FIG. In this state, the motor drive is continued. For example, when the maximum output torque of the motor 4 is 100 Nm, the motor driving is continued with the upper limit torque being suppressed to 20 Nm.
After time t1, the generator 2 is stopped and the switching element of the generator inverter 6b does not generate heat, so the switching element temperature (average value Tswg_ave) of the generator inverter 6b gradually decreases.

  At time t2, the difference between the average value Tswg_ave of the switching element temperature of the generator inverter 6b and the coolant temperature (60 ° C.) before the coolant temperature sensor 12 indicated by A fails is set in advance. The difference Tdiff (for example, 5 ° C.) is within, that is, the average value Tswg_ave is 65 ° C. or less, and it is determined that the average value Tswg_ave of the switching element temperature of the generator inverter 6b coincides with the cooling water temperature Tw. The average value Tswg_ave of the detected values based on the switching element temperature is recognized as the cooling water temperature Tw. As a result, according to the motor maximum output torque suppression map of FIG. 4, the cooling water temperature is set to the average value Tswg_ave of the switching element temperature of the generator inverter 6b, and the motor drive is performed with the motor maximum output torque suppression rate 1.0 corresponding to this. Will continue.

  Thus, even if the cooling water temperature sensor 12 fails, until the correct cooling water temperature can be detected, the motor maximum output torque suppression map assuming that the cooling water temperature is the maximum water temperature (110 ° C.) is used. After the maximum output torque is suppressed and the correct coolant temperature can be detected, the vehicle can continue to operate with the motor without suppressing the maximum output torque. The switching element of the inverter can be protected from overheating while minimizing the sense of discomfort.

  In the above-described embodiment, the motor inverter 6a and the generator inverter 6b each have a plurality of switching element temperature sensors, and the average value Tswg_ave of the detection values of the plurality of switching element temperature sensors is obtained. When one switching element temperature sensor is provided in each of 6a and the generator inverter 6b, the detection value of the switching element temperature sensor may be used.

1 engine, 2 generator, 3 clutch, 4 motor, 5 tires,
6a Inverter for motor, 6b Inverter for generator, 7 Battery,
8 inverter cooling device, 9 cooling water piping, 10 electric (water) pump,
11 Radiator, 12 Cooling water temperature sensor, 13a Inlet part, 13b Outlet part,
13c water jacket, 14 EV-ECU,
14a Cooling water temperature sensor failure detection unit, 14b Travel mode determination unit,
14c motor maximum output torque suppression unit,
14d Cooling water temperature sensor failure detection value reading section,
14x electric vehicle control unit, 15 vehicle speed sensor, 16 accelerator opening sensor,
17 motor rotation speed sensor, 18 generator rotation speed sensor,
19 Engine rotation speed sensor, 105Ha-107Lb switching circuit,
105HaU-107LbW switching element temperature sensor,
105a, 105b U-phase switching circuit,
106a, 106b V-phase switching circuit,
107a, 107b W-phase switching circuit,
109a, 109b upper arm, 110a, 110b lower arm,
141 interface, 142 CPU, 143 memory, M storage unit,
MG motor generator.

The present invention includes an inverter for a motor and an inverter for a generator, converts a power from a battery to drive a motor, converts a power from a generator and stores it in the battery, and each inverter. An inverter cooling device for cooling with cooling water, a switching element temperature sensor for detecting the temperature of the switching element of each inverter, and a sensor group mounted on the electric vehicle including a cooling water temperature sensor for detecting the temperature of the cooling water; A control unit that controls the electric vehicle, and the control unit switches the EV driving mode and the power generation driving mode according to a detection value from the sensor group, and controls the electric vehicle. And the electric vehicle control unit detects a failure of the cooling water temperature sensor in accordance with a detection value from the cooling water temperature sensor. A cooling water temperature sensor failure detection unit, and a detection detected by the switching element temperature sensor of the switching element of the generator inverter when a failure of the cooling water temperature sensor is detected in the EV travel mode. A coolant temperature sensor failure detection value reading unit whose value is a detected value of the coolant temperature , and further, the control unit has a storage unit, and the electric vehicle control unit has a motor maximum output torque. The cooling water temperature sensor failure detection unit stores the detection value of the cooling water temperature sensor in the storage unit in time series, and the electric vehicle control unit is in the power generation travel mode. When the failure of the cooling water temperature sensor is detected, the driving of the generator is stopped, and the motor maximum output torque suppression unit performs the motor according to the detection value from the cooling water temperature sensor. The difference between the detected value of the cooling water temperature before the failure is detected by suppressing the maximum output torque and the detected value detected by the switching element temperature sensor of the switching element of the generator inverter is larger than the set value In this case, the maximum output torque of the motor is suppressed, and if it is within the set value, the detected value reading unit at the time of failure of the cooling water temperature sensor is detected by the switching element temperature sensor of the switching element of the generator inverter. The detected value is used as a detected value of the temperature of the cooling water in a control device for the electric vehicle.

Claims (4)

A power drive unit having a motor inverter and a generator inverter, converting the power from the battery to drive the motor, and converting the power from the generator to store in the battery;
An inverter cooling device for cooling each inverter with cooling water;
A sensor group mounted on an electric vehicle, including a switching element temperature sensor that detects a temperature of a switching element of each inverter, and a cooling water temperature sensor that detects a temperature of the cooling water;
A control unit for controlling the electric vehicle;
With
The control unit has an electric vehicle control unit that controls the electric vehicle by switching between an EV travel mode and a power generation travel mode according to a detection value from the sensor group,
The electric vehicle controller is
A cooling water temperature sensor failure detection unit that detects a failure of the cooling water temperature sensor according to a detection value from the cooling water temperature sensor;
When a failure of the cooling water temperature sensor is detected in the EV travel mode, the detected value detected by the switching element temperature sensor of the switching element of the generator inverter is the detected value of the cooling water temperature. The cooling water temperature sensor failure detection value replacement unit,
The control apparatus of the electric vehicle containing. The control unit is
Having a storage unit,
The electric vehicle controller is
A motor maximum output torque suppressor;
Including
The cooling water temperature sensor failure detection unit stores the detection value of the cooling water temperature sensor in the storage unit in time series,
When the electric vehicle control unit is in the power generation travel mode and the failure of the coolant temperature sensor is detected, the driving of the generator is stopped,
The motor maximum output torque suppression unit suppresses the maximum output torque of the motor according to the detection value from the cooling water temperature sensor, and detects the cooling water temperature before detecting the failure, and the generator inverter. When the difference between the detection value of the switching element detected by the switching element temperature sensor is larger than the set value, the maximum output torque of the motor is suppressed,
When the value is within the set value, the detected value detected by the switching element temperature sensor of the switching element of the generator inverter is detected by the cooling water temperature sensor failure detection value replacement unit. And
The control apparatus of the electric vehicle of Claim 1. Each of the inverters is provided with a plurality of the switching element temperature sensors,
The detection value detected by the switching element temperature sensor of the switching element of the generator inverter is an average value of the detection values detected by the plurality of switching element temperature sensors of the generator inverter. The control apparatus of the electric vehicle as described in any one of. The inverter for the motor and the inverter for the generator are used to drive the motor by converting the power from the battery, and the power drive unit that converts the power from the generator and stores it in the battery is cooled with cooling water. While
The EV travel mode and the power generation travel according to detection values from a sensor group mounted on the electric vehicle, including a switching element temperature sensor for detecting the temperature of the switching element of each inverter and a cooling water temperature sensor for detecting the temperature of the cooling water. Switch the mode to control the electric vehicle,
Detecting a failure of the cooling water temperature sensor according to a detection value from the cooling water temperature sensor;
When a failure of the cooling water temperature sensor is detected in the EV travel mode, the detected value detected by the switching element temperature sensor of the switching element of the generator inverter is the detected value of the cooling water temperature. A method for controlling an electric vehicle.

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